Detergent composition



3,039,312 DETERGENT COMPGSITION Victor Mills, (Iincinnati, Ohio, assignor to The Procter 8; gamble Company, Cincinnati, Ohio, a corporation of no No Drawing. Filed Aug. 16, 1952, Ser. No. 304,853 1t} Claims. (Cl. 252-161) This invention relates to wetting, sudsing and detergent compositions.

More particularly, this invention relates to wetting, sudsing and detergent compositions in small solid particle form, such as spray-dried granules, which have improved anti-caking properties.

A number of synthetic detergent products when in small solid particle form exhibit the very undesirable tendency to lose their free-flowing properties and cake or form lumps while in storage on the retail dealers shelves. This tendency is particularly apparent in products containing Water soluble salts of alkyl aryl sulfonic acids, such as, for example, sodium alkyl benzene sulfonate, whether the alkyl aryl sulfonate comprises the sole active ingredient of the detergent composition or is in admixture with various other types of synthetic organic detergents, the mixture comprising the active portion of the detergent composition. This caking and lumping tendency is enhanced by the presence of atmospheric heat and moisture and therefore such products tend to lose their free-flowing characteristics much more readily while in storage under conditions prevailing during the summer months.

It is an object of my invention to improve the anticaking properties of detergent compositions which contain water soluble salts of alkyl aryl sulfonic acids as an active organic detergent ingredient and which show a tendencyto cake or lump.

Further objects will be apparent from the following description.

I have found that if methyl sulfate, normally in the form of a water-soluble salt, and particularly the sodium salt, is incorporated in a product exhibiting the characteristics described above, the tendency of the product to cake and form lumps is markedly reduced.

Although I prefer to use amounts of the methyl sulfate salt equivalent to about 2% to about 6% by weight of the final detergent product, amounts less than 2%, for example, about 1.5%, may be used to advantage. Also, amounts in excess of 6%, for example, up to about 10%, may be employed without undue v adverse effects. Amounts in excess of 10% may be used but there is no apparent advantage in using such greater amounts. In fact, some undesirable effects, such as a decrease in detergency, have been noted when such larger quantities are present in the detergent. product.

.Other advantages may also be realized from the incorporation of methyl sulfate into such products. For example, in the production of the sulfonated type of detergent which comprises, in general, mixing and react= ing sulfonatable organic material with a suitable sulfonating agent and neutralizing the resulting acid mixture with an alkaline material, most commonly sodium hydroxide, the neutralized mixture, when sodium hydroxide or a sodium salt is used as the neutralizing agent, comprises a substantial percentage of sodium sulfate. This salt contributes little if anything of value to the finished prod- 3&30312 Patented Apr. 17, 1962 net in the way of detergency and has in fact been considered by various persons to have inherent disadvan tages (such as a tendency to increase the redeposition of soil on washed textile articles) when present in products or" this type. In the detergent compositions of my invention when the hereinafter referred to method of Korpi and Whyte is used as the means for incorporating a methyl sulfate salt, a portion of the sodium sulfate present in the product is in effect replaced by the methyl sulfate salt and thus the undesirable characteristics attributed to the presence of sodium sulfate are to that extent minimized.

l'n the production of a solid granular type of product with which we are primarily here concerned, the neutralized reaction mixture referred to above is normally mixed with various other materials which may be desirably present in such products, e.g. inorganic builders like the alkali metal phosphates, silicates and carbonates and organic additives like carboxymethyl cellulose, higher fatty alcohols and various amides, and this mixture is then subjected to a spray-drying operation as is well known in the art. In a typical spray-drying operation such a mixture is first prepared in a flowing condition which is referred to in the art as a paste. This paste is then pumped through a spray nozzle which atomizes it into the upper part of a chamber or tower containing a column of air which has been heated to a temperature in the range from about 2 0-500 F. and which may pass in either concurrent or countercurrent direction to the sprayed mixture to evaporate the water from the falling atomized particles.

It has been observed that with such a spray-dried granular product the incorporation of methyl sulfate into the detergent composition promotes the formation of a tougher, moreresilient particle. As a result, individual particles making up the finished products are more capable of withstanding mechanical handling without disintegration and therefore products incorporating methyl sulfate tend to be less dusty than products prepared without methyl sulfate. A further advantage has been noted in that the finished product incorporating methyl sulfate appeared slightly whiter than similar products without methyl sulfate.

My invention is not limited to any particular method of incorporating the methyl sulfate into the detergent compositions and any satisfactory method may be used. For example, the methyl sulfate may be crutched into the detergent mixture when it is in paste form just prior to spray-drying or it may be added according to the metl 0d outlined in the Korpi and Whyte application, SN. 289,434, filed May 22, 1952, now Patent No. 2,742,435.

Since it is known that in detergent products in small solid particle form which contain an alkylaryl sulfonate as the active ingredient the tendency to cake and form lumps is particularly apparent, and since I have found that the incorporation of sodium methyl sulfate into any product of this type which exhibits the calcing and lumping tendency will appreciably reduce such tendency and result in a product having improved anti-caking prop erties, it is to be appreciated that my invention finds application not only in those products which contain an alkyl aryl sulfonate as the sole active organic detergent ingredient and which exhibit the tendency to cake and lump but also in those products exhibiting such tendency wherein the allcyl aryl sulfonate comprises only a portion of the active organic detergent ingredients (e.g. products wherein the active ingridents comprise a mixture of an alkyl benzene sulfonate and an alkyl sulfate, the alkyl chains in each case containing from eight to about twenty-two carbon atoms). Thus, detergent compositions having from about 15% to about 95% of alkyl aryl sulfonate as an active organic detergent ingredient may be improved as to anti-caking properties by means of my invention.

It is also to be appreciated that my invention may be advantageously employed with highly built" detergent compositions which contain a water soluble salt of an alkyl aryl sulfonic acid as an active ingredient and which exhibit the caking and lumping tendency as well as with those compositions wherein such organic detergent ingredient comprises a major portion of the detergent composition. For example, those detergent compositions which contain at least 15% by weight of an alkyl aryl sulfonate as the active organic detergent ingredient and sodium tripolyphosphate as a builder, and in which the ratio of sodium tripolyphosphate to the active organic detergent ingredient varies from about 1:1 to about :1 are benefitted by my invention.

Furthermore, similar results as to improved anticaking properties may be obtained with products in finely divided form other than spray-dried products, such as, for example, those obtained by drum drying operations, from a soap flake dryer, or from extruded threads of a detergent mixture.

A method of determining the caking values of the various detergent products in small particle form is set forth immediately below. The test is normally run under rather drastic conditions of temperature and humidity which promote the tendency of the products to cake and lump. This is to simulate the storage conditions the product is subjected to on the retailers shelves during the summer months. It is to be understood of course that, if desired, other conditions of temperature and humidity may be used in the testing procedure.

Samples to be tested are packaged as they would be for normal retail use, i.e., in cartons which have received no special moisture-proofing treatment, and are then placed in a cabinet in which air of fixed temperature and humidity (e.g. 90 F. at 80% relative humidity) is circulated. After storage for varying lengths of time, depending upon the storage conditions which are to be simulated, the samples are graded according to the ease with which they pour from the carton, the amount of product present in the form of lumps and the amount of product which is hung-up on the sides of the carton. The samples may be either poured from the carton by hand or, to eliminate the possibility of human error, by machine. The grading scale covers the range from O to 100, a grade of 0 representing a product that cannot be removed from the carton without tearing the carton open and a grade of 100 representing a product that pours like dry sand. The actual grade is the amount of the product in terms of percent, based on the total amount of product in the carton, which will pour out and pass through a wire screen having a inch mesh.

In the following examples, which are not to be considered limiting but are merely to serve to more fully describe my invention, the caking values were determined according to the above described method.

Example 1.Two samples of a spray-dried detergent composition were prepared. The active ingredient of each sample was principally dodecyl benzene sulfonate and comprised about 26% by weight of the composition. The remainder of the detergent composition comprised essentially sodium sulfate along with other additives in minor amounts. One sample contained 4% sodium methyl sulfate by weight of the product as a caking inhibiting agent and the other sample contained no sodium methyl sulfate. These products were packed in paperboard cartons typically used for such a product,

Table I Granule Gaking Grade Amount of Sodium Methyl Sulfate Present At 1 At 3 At 5 At 7 Day Days Days Days None 76 25 l7 l4 4% 98 95 s9 23 It may be seen from the above data that the sodium methyl sulfate is very effective in inhibiting the caking tendencies of the detergent product.

Example 2.--Two samples of a spray-dried composition containing an alkyl benzene, the alkyl chain of which contained an average of about 12 carbon atoms, in an amount equal to about 26% by weight of the detergent composition, as the active ingredient were prepared. The remainder of the composition comprised essentially sodium sulfate along with other additives in minor amounts. One of the samples contained about 2% by weight of sodium methyl sulfate and the other sample contained no sodium methyl sulfate and was used as a blank for comparison purposes. These products were packed into paperboard cartons as specified in Example 1, and their caking values were determined after storage for varying lengths of time at 90 F. and 80% relative 1 Coking value before storing under conditions specified.

Here again it may be seen that the incorporation of sodium methyl sulfate markedly inhibits the caking tendency of an alkyl benzene type detergent.

Example 3.Two samples of a spray-dried detergent composition, containing about 26% active ingredient, 75% of which was an alkyl benzene sulfonate and 25% of which was an alkyl sulfate whose alkyl chain was obtained from the high molecular weight fatty alcohols derived from coconut oil, were prepared. The remainder of the detergent composition comprised essentially sodium sulfate along with other additives in minor amount. One sample contained 4% sodium methyl sulfate as a caking inhibitor and the other sample, containing no sodium methyl sulfate, was used as a blank for comparison purposes.

These samples were packed into cartons as specified in Example 1 and caking determinations were made after storage at F. and 80% relative humidity with the following results.

Example 4.-A sample of a spray-dried detergent composition was prepared which contained, as the active ingredient, 18.3% by weight of an alkyl benzene sulfonate, the alkyl chain of which contained an average of about 12. carbon atoms, 44.5% sodium tripolyphosphate, and 4% sodium methyl sulfate as the caking inhibitor, as well as other minor constituents.

A second comparable sample, containing 16.4% of the same active ingredient as above, 46% sodium tripolyphosphate, and the same minor constituents, but no sodium methyl sulfate, was prepared for comparison purposes. It is to be appreciated that the slight variations in the amounts of the various constituents, other than sodium methyl sulfate, of the detergent compositions compared have no significant efiect on the caking values of the products.

Samples of these compositions were packed into cartons as specified in Example 1 and caking determinations were made after storage at 90 F. and 80% relative humidity. Th results appear below.

Table IV Fresh Pour At 3 Days At 7 Days 1 1 The double figures in these columns denote two separate caking grade determinations.

It may be readily seen from-the above that the incorporation of sodium methyl sulfate into a highly built detergent greatly increases its anti-caking properties.

It is to be appreciated that in any of the foregoing examples any water-soluble salt of methyl sulfate such as, for example, the magnesium or potassium salts, may be substituted for sodium methyl sulfate with comparable results.

Having thus described my invention, what I claim is:

1. A wetting, sudsing and detergent composition in small solid particle form which comprises a mixture of an organic detergent agent, selected from the group consisting of water soluble salts of alkyl substituted mononuclear aryl sulfoni: acids and mixtures thereof with water soluble salts of alkyl sulfuric acid esters, all containing from 8 to 22 carbon atoms in the alkyl chain, the said organic detergent agent being characterized by its tendency to promote caking in detergent compositions and a water soluble salt of methyl sulfate in an amount at least 1.5% by weight of the detergent composition and sufi'icient to inhibit the caking thereof.

2. The wetting, sudsing and detergent composition of claim 1 whereinthe organic detergent agent is a water Days 1 soluble salt of an alkyl substituted mononuclear aryl sulfonate the alkyl chain of which contains from 8 to 22 carbon atoms and comprises not less than about 15% by weight of the composition.

3. The wetting, sudsing and detergent composition of claim 1 wherein the water soluble salt of methyl sulfate is sodium methyl sulfate.

4. The wetting, sudsing and detergent composition of claim 3 wherein the organic detergent agent is a water soluble salt of an alkyl benzene sulfonate, the alkyl chain of which contains from 8 to 22 carbon atoms.

5. The wetting, sudsing and detergent composition of claim 3 wherein the organic detergent agent is a mixture of water soluble salts of an alkyl benzene sulfonate and water soluble salts of an alkyl sulfate, the alkyl chain in each case containing from 8 to 22 carbon atoms.

6. The wetting, sudsing and detergent composition of claim 3 wherein the sodium methyl sulfate is present in an amount from about 2% to about 6% by weight of the composition.

7. The wetting, sudsing and detergent composition of claim 3 wherein the sodium methyl sulfate is present in an amount equal to about 4% by weight of the compm sition.

8. A wetting, sudsing, and detergent composition in small solid particle form which comprises a mixture of an organic detergent agent selected from the group consisting of water-soluble salts of alkyl substituted mononuclear aryl sulfonic acids and mixtures thereof with water-soluble salts of alkyl sulfuric acid esters, the alkyl chain in each case containing from 8 to 22 carbon atoms, the said organic detergent agent being characterized by its tendency to promote caking in detergent compositions,

as an organic detergent agent, a sodium alkyl substituted mononuclear aryl sulfonate, the alkyl chain of which contains from 8 to 22 carbon atoms, the said organic detergent agent being characterized by its tendency to promote caking in detergent compositions, and a caking inhibiting amount of a water-soluble salt of methyl sulfate.

References Cited in the file of this patent UNITED STATES PATENTS Lewis Mar. 17, 1953 Korpi Apr. 17, 1956 

1. A WETTING, SUDSING AND DETERGENT COMPOSITON IN SMALL SOLID PARTICLES FORM WHICH COMPRISES A MIXTURE OF AN ORGANIC DETERGENT AGENT, SELECTED FROM THE GROUP CONSISTING OF WATER SOLUBLE SALTS OF ALKYL SUBSTITUTED MONONUCLEAR ARYL SULFONIC ACIDS AND MIXTURES THEREOF WITH WATER SOLUBLE SALTS OF ALKYL SULFURIC ACID ESTERS, ALL CONTAINING FROM 8 TO 22 CARBON ATOMS IN TEH ALKYL CHAIN, THE SAID ORGANIC DETRGENT AGENT BEING CHARACTERIZED BY ITS TENDENCY TO PROMOTE CAKING IN DETERGENT COMPOSITIONS AND A WATER SOLUBLE SALT OF METHYL SULFATE IN AN AMOUNT AT LEAST 1.5% BY WEIGHT OF TEH DETERGENT COMPOSITION AND SUFFICIENT TO INHIBIT THE CAKING THEREOF. 